Serial dilution
Per step
Tubes
| Tube | Concentration | Diluent | Transfer in | Final volume |
|---|---|---|---|---|
| 1 | 100 µM | 0.9 mL | 0.1 mL from stock | 0.9 mL |
| 2 | 10 µM | 0.9 mL | 0.1 mL from tube 1 | 0.9 mL |
| 3 | 1 µM | 0.9 mL | 0.1 mL from tube 2 | 0.9 mL |
| 4 | 100 nM | 0.9 mL | 0.1 mL from tube 3 | 0.9 mL |
| 5 | 10 nM | 0.9 mL | 0.1 mL from tube 4 | 0.9 mL |
| 6 | 1 nM | 0.9 mL | 0.1 mL from tube 5 | 1 mL |
Method & reference
Plan a dilution series tube by tube.
Each tube holds volume V. For factor f, transfer V ÷ f into V − V ÷ f of diluent, so tube i has C₀ ÷ fⁱ. "1 in n" means n-fold; "1 + n" means (n + 1)-fold. Target mode uses f = (C₀ ÷ Cfinal)^(1 ÷ steps).
What is the difference between a 1-in-10 and a 1+10 dilution?
A 1-in-10 dilution is one part sample in ten parts total, a 10-fold dilution. A 1+10 dilution is one part sample plus ten parts diluent, an 11-fold dilution. Protocols mix these up constantly, so the calculator names both explicitly.
How do I plan a standard curve from 1 mM down to 1 nM?
Choose the target mode with a final concentration of 1 nM over 6 steps. The calculator finds the constant factor, here 10-fold, and lists the transfer and diluent volume for every tube.
Why should I discard the transfer from the last tube?
So that every tube ends up with the same final volume. Without discarding, the last tube holds the full volume while the others hold the volume minus the transfer.